1. Field of the Invention
The present invention relates to a planting device for plants and a planting structure in which the device is used.
The present invention relates to a device for cultivating garden trees, flowering plants and other plants easily. In particular, the present invention relates to a planting device for growing plants that is mounted on a rooftop or a roof of a building and also to a water supplying and draining board for loading soil in such a planting device.
2. Description of the Related Art
In recent years, a growing number of attempts have been made for planting plants on rooftops of buildings and in other spaces on a large scale to green inorganic spaces in an urban area.
For this purpose, in most cases, a holddown concrete layer is formed on a waterproof layer on a slab surface of a building and the like, on which a gravel layer composed of sand, gravel and the like as well as a soil dressing layer are alternately laminated as a planting layer for planting plants.
However, in order to provide sufficient water retainability and water drainability for cultivating plants, a relatively large quantity of sediment must be introduced in a waterproof layer, and the concrete layer is also considerably heavy. The combined weight of these two layers affects a building, which is a problem.
The present inventor has disclosed a lightweight planting device which is excellent in water retainability and water drainability (for example, Japanese Published Unexamined Patent Application No. 2531542).
According to the above-described planting device, a waterproof layer is fixed on a slab surface formed on a rooftop of a building or the like, a water retaining member having a nonwoven fabric and the like, and a water retaining/supply/draining means composed of a drain panel having recessed parts and projected parts and the like are provided on the upper surface of the waterproof layer, a planting layer composed of a gravel layer and a soil dressing layer is laminated above the water retaining/supply/draining means, and a proper water retainability and drainability is attained by the water retaining/supply/draining means.
Therefore, this device has eliminated the necessity for a concrete layer which is provided for draining, thereby making it possible to establish a planting layer with a necessary minimum thickness, for example, 50 mm, with consideration given to the length of the root hairs of plants, owing to the improvement in water retainability.
The followings are prior art literature related to the present invention.
[Patent Document 1] Japanese Published Unexamined Patent Application No 2531542
[Patent Document 2] Japanese Published Unexamined Patent Application No 2717632
Accordingly, the above-described conventional planting device achieves the advantage that the weight of the entire device is reduced to avoid an adverse effect on a building. However, such a prior art device still has several problems which need to be improved.
Namely, the conventional device is complicated in structure and includes a large number of components, thereby raising costs of the device or structure and resulting in poor installation efficiency.
Further, this type of conventional device needs various kinds of maintenance work and such work is extremely difficult due to the absence of a scaffold. For example, watering must be done over the surface of the soil of each of the devices and a uniform spraying of water all over the entire soil surface of the device is difficult particularly due to the absence of a scaffold, thereby complicating the work resulting in a longer time to complete the watering.
Also, in such a conventional device, where a construction surface on which greening is carried out is a gradient, the device cannot be formed continuously in a satisfactory manner, causing problems in watering in particular. To be more specific, at such an installation having a gradient, watering must be done at each device, which is much more complicated and difficult due to the gradient as compared to an installation at a flat location.
Technology which can solve this drawback has been disclosed in Japanese Published Unexamined Patent Application No. 2717632. However, in this technology, fixing the device to the rooftop is complicated, resulting in an increase in the installation costs and the time needed in the installation, which is a problem.
The present inventor and the like have been actively engaged in the research and development of a newer planting device and have registered Japanese Patent No. 3280912, Japanese Patent No. 3286753 and Japanese Patent No. 3328583 with regard to such a planting device. However, in the above-described planting devices, a drain plate (water retaining/supply/draining means) and a truncated cone-shaped hollow body used as the fixing means are formed integrally and made complicated in shape and larger in size as a whole. Therefore, where resin is used to form a drain panel, it is not easy to manufacture a mold, thereby increasing costs. Further, it is complicated and requires some work to store and transport such products.
For solving the above problems, a drain panel and a hollow body are constituted with a separate member. Such an attempt has been made that at first, the hollow body is formed and fixed, the drain panel is then formed through the hollow body at an opening part of the drain panel. There is, however, a difficulty in aligning the one member with the other, resulting in poor work efficiency, which is a problem.
Further, since the above-described conventional hollow body is uniform in height, it is necessary to change the thickness of the soil bed, depending on the installation state of the planting devices. Such necessity is not always met and this poses another problem.